There are many patent documents and commercial products describing tail pieces, endpins, and end piece receptacles for stringed musical instruments such as a cello, bass or the like. The approach often taken specifies the specific shapes and materials defining the structure of the endpins and receptacles. Arguments are then made as to why these designs will give a desired performance related to timber, loudness, and tone. Examples of the patent documents are U.S. Pat. No. 6,127,611 by VanEvers, U.S. Pat. No. 4,018,129 by Hollander, 2006/0278059 by Gipson. DeVuono's prior art patent, U.S. Pat. No. 6,998,523, and D658,162S are included in these documents. However, there does not exist a general approach to quickly modify the design to customize the acoustic outcomes of these designs. Therefore, there is a need for a design approach that allows the user to quickly make modifications to the device to achieve a favorable acoustic outcome.